血清中神经来源外泌体MicroRNA-211-5p与帕金森病认知障碍的相关性及诊断意义

Association of serum neurogenic exosome MicroRNA-211-5p with cognitive impairment in Parkinson's disease and its diagnostic value

目的:探索血清中神经来源的外泌体中MicroRNA-211-5p(miR-211-5p)的水平和脑源性神经营养因子(BDNF)水平与帕金森病(PD)认知障碍的相关性和诊断意义。方法:选择2017年1月至2018年4月于嘉兴市第二医院就诊的帕金森病患者80例(PD组),根据蒙特利尔认知评估量表将患者分为认知障碍36例,非认知障碍44例。同时选择同期体检的健康人30例作为对照组。取受试者外周血后采用ExoQuick试剂盒提取外泌体,L1细胞黏附分子(L1CAM)生物素化抗体分离神经来源的外泌体。采用酶联免疫吸附法(ELISA)检测外泌体中BDNF的水平,实时荧光定量PCR(RT-QPCR)检测外泌体中miR-211-5p的表达水平。结果:(1)血清神经来源外泌体中BDNF和miR-211-5p具有相关性(r=-0.805,P<0.001),PD组血清神经来源外泌体中BDNF和miR-211-5p具有相关性(r=-0.785,P=0.002),对照组亦具有相关性(r=-0.867,P<0.001)。(2)PD组患者血清神经源外泌体中miR-211-5p的水平为(0.30±0.08)显著高于对照组(0.17±0.04),而BDNF水平为(0.55±0.06)mg/L,低于对照组(0.75±0.06)mg/L,(t=7.125、6.368,均P=0.000)。(3)认知障碍组患者血清神经源外泌体中BDNF水平为(0.45±0.07)mg/L,低于非认知障碍组(0.63±0.07)mg/L和对照组(0.75±6.54)mg/L,(t=8.999、7.608,均P=0.000)。而miR-211-5p为(0.36±0.07)显著高于非认知障碍组(0.24±0.05)和对照组(0.17±0.04),(t=10.923,7.520,均P=0.000)。(4)ROC曲线结果显示miR-211-5p作为PD认知障碍的曲线下面积为0.860(95%CI:0.770~0.950)阈值为0.32。BDNF作为PD认知障碍的曲线下面积为0.891(95%CI:0.822~0.961)阈值为0.67。(5)miR-211-5p的靶基因可能是BDNF,可能通过抑制BDNF的mRNA表达降低BDNF的水平。结论:人血清神经源性外泌体miR-211-5p在PD认知障碍中高表达,可以作为PD认知障碍的诊断标准之一,其作用可能与BDNF mRNA表达抑制有关。

Objective To explore the correlation of serum neurogenic exosome MicroRNA-211-5p(miR-211-5p)levels and brain derived neurotrophic factor(BDNF)levels with cognitive impairment in patients with Parkinson's disease and their diagnostic value.Methods A total of 80 patients with Parkinson's disease(PD)admitted to the Second Hospital of Jiaxing City from January 2017 to April 2018 were enrolled.According to the Montreal cognitive assessment scale,patients were divided into the cognitive impairment group(n=36)and the non-cognitive impairment group(n=44).Meanwhile,30 healthy people who took health check-ups during the same period were selected as the control group.Exosomes were extracted from peripheral blood of subjects by using the ExoQuick kit,and the neurogenic exosomes were separated by an L1 cell adhesion molecule(L1CAM)biotinylated antibody.BDNF levels in the exosomes were measured with an enzyme-linked immunosorbent assay(ELISA),and the expression level of miR-211-5p in the exosome was determined by real-time fluorescence quantitative PCR(RT-QPCR).Results There was a correlation between BDNF and miR-211-5p(r=-0.805,P<0.001)in serum neurogenic exosomes(r=-0.805,P<0.001).BDNF was correlated with miR-211-5p in both the PD and control groups(r=-0.785 and-0.867,P=0.002 and 0.001).The miR-211-5p level was higher and the BDNF level was lower in the PD group than in the control group(0.30±0.08 vs.0.17±0.04,0.55±0.06 mg/L vs.0.75±0.06 mg/L,t=7.125 and 6.368,P=0.000 and 0.000).The BDNF level was lower(0.45±0.07 mg/L vs.0.63±0.076.368 and 0.75±0.08 mg/L,t=8.999 and 7.608,P=0.000 and 0.000)and the MiR-211-5p level was higher(0.36±0.07 vs.0.24±0.05 and 0.17±0.04,t=10.923 and 7.520,P=0.000 and 0.000)in the cognitive impairment group than in the non-cognitive impairment and control groups.The receiver-operating characteristics(ROC)curve showed that the area under the curve of miR-211-5p as a measure for cognitive impairment in Parkinson's disease was 0.860(95%CI:0.770-0.950)with a threshold of 0.32.The area under the curve of BDNF as a measure for cognitive impairment in Parkinson's disease was 0.891(95%CI:0.822-0.961)with a threshold of 0.67.BDNF seemed to be the target gene of miR-211-5p,since the latter could inhibit BDNF expression by reducing BDNF mRNA levels.Conclusions Human serum neurogenic exosome miR-211-5p is highly expressed in PD patients with cognitive impairment and has the potential to be used as one of diagnostic parameters for cognitive impairment in PD patients.The high expression of serum neurogenic exosome miR-211-5p may be related to the inhibition of BDNF by reducing its mRNA levels.